Diagnosing Alzheimer's: An interview with a Mayo Clinic specialist

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Diagnosing Alzheimer's: An interview with a Mayo Clinic specialist

photo of Eric Tangalos, M.D.
Eric Tangalos, M.D.

In this interview, Eric Tangalos, M.D., a primary care physician and co-director for education at the Alzheimer's Disease Research Center at Mayo Clinic, Rochester, Minn., explains the diagnostic process when a person is experiencing memory problems or other impairments in thinking skills. An accurate diagnosis is a critical first step that helps ensure appropriate treatment, care, family education and plans for the future.

How can people recognize the early signs of Alzheimer's?

The Alzheimer's Association has a list of 10 warning signs that can help you recognize early indications:

  1. Memory loss that disrupts daily life
  2. Challenges in planning or solving problems
  3. Difficulty completing familiar tasks at home, at work or at leisure
  4. Confusion with time or place
  5. Trouble understanding visual images and spatial relationships
  6. New problems with words in speaking or writing
  7. Misplacing things and losing the ability to retrace steps
  8. Decreased or poor judgment
  9. Withdrawal from work or social activities
  10. Changes in mood and personality

An important factor is that problems affect how well a person functions in everyday life. For example, it's easy to forget where you've parked your car in a parking lot. That's happened to all of us, but most of us eventually find our cars. People with Alzheimer's disease may not only forget the car's location but also lose the ability to adjust and solve the problem of the lost car.

When warning signs of Alzheimer's disease appear, it's important for a person to get a prompt and accurate diagnosis.

How does a doctor make a diagnosis of Alzheimer's?

The primary tools we use to diagnose Alzheimer's disease are tests we can perform in the office or clinic. Additional laboratory tests or brain-imaging tests also provide useful information for diagnosis, including ruling out other diseases that cause similar symptoms. Our goal is to answer the following questions:

  • Does a person have an impairment in memory or other thinking skills?
  • Does a person exhibit changes in personality or behaviors?
  • What is the degree of impairment or change?
  • How do the problems affect the person's ability to function?
  • What is the cause of the symptoms?

What diseases are you trying to rule out?

We check the thyroid, to rule out problems there. And, in many cases, symptoms of depression can be mistaken for Alzheimer's — and vice versa. We also routinely look for vitamin B-12 deficiency.

And we always make sure that the person is generally healthy and doesn't have some other serious medical problem that would complicate the diagnosis. A lot of older people have other medical problems that just make things worse — such as heart disease, high blood pressure, strokes, diabetes, kidney disease, lung disease or any combination of these.

How do you assess memory problems and other symptoms?

We conduct relatively simple, objective tests in which we ask people to answer questions or perform tasks associated with memory, abstract thinking, problem solving, language usage and related skills that we collectively refer to as cognitive skills. Scores on such tests enable us to quantify with some reliability a person's degree of cognitive impairment.

  • Assessing daily living skills. We use questionnaires to judge a person's ability to perform activities of daily living (ADLs). These tasks include such things as using a telephone, preparing meals, taking medications and handling finances. A family member, friend or caregiver may be asked to help with the questionnaire. An ADL score helps us quantify how well a person functions.
  • Neuropsychological tests. These tests, can help us identify and judge the severity of behaviors that are commonly observed in people with Alzheimer's disease. They may also demonstrate that a person is experiencing depression or other mental health problems that may cause similar symptoms.
  • Talking with friends and family. We may also have more general questions, particularly for a family member or friend of the person with cognitive symptoms. We're looking for things that don't fit with the individual's former level of function. The family member or friend can often explain how cognitive skills, functional abilities and behaviors have changed over time.

This series of clinical assessments and a general physical exam often provide enough information to make a diagnosis of Alzheimer's disease. But when the diagnosis isn't clear, we depend on additional tests.

What lab tests do you use?

The primary role of lab tests — usually with blood samples — is to rule out other disorders that can cause some symptoms similar to those of Alzheimer's disease, such as a thyroid disorder or vitamin B-12 deficiency.

What is the current role of brain-imaging tests?

Alzheimer's disease results from the progressive loss, or degeneration, of brain cells. This degeneration can show up in a variety of ways in brain scans. But these scans alone aren't enough to make a diagnosis. This is because there's a lot of overlap in what we consider normal age-related change in the brain and abnormal change.

But brain imaging can help:

  • Rule out other causes, such as hemorrhages, brain tumors or strokes
  • Distinguish between different types of degenerative brain disease
  • Establish a baseline about the degree of degeneration

The brain-imaging technologies most often used are:

  • Computerized tomography (CT), which is a specialized X-ray technology that produces thin cross-sectional images of the brain
  • Magnetic resonance imaging (MRI), which uses magnetic fields and radio waves to create either cross-sectional or 3-D images of the brain

What does the future of diagnosis look like?

Researchers are working on new diagnostic tools that may enable us to diagnose Alzheimer's disease earlier in the course of the disease, when symptoms are very mild or before symptoms appear. Scientists are investigating a number of disease markers — genes, disease-related proteins and imaging procedures — that may accurately and reliably indicate whether someone has Alzheimer's disease and how much the disease has progressed. However, more research on these tests is necessary.

What's the benefit of an early diagnosis?

Reluctance to go to the doctor when you or a family member has memory problems is understandable. People hide their symptoms, or family members cover for them. That's easy to understand because Alzheimer's is such a dreaded disease. And many people wonder if there's any point in a diagnosis if there's no cure for the disease.

It's true that if a person has Alzheimer's or a related disease, we can't offer a cure. But getting an early diagnosis can be beneficial. If a person has another treatable condition that's causing the cognitive impairment or somehow complicating the impairment, then we can start treatments.

And for those with Alzheimer's disease, we can offer drug and nondrug interventions that may ease the burden of the disease. We usually prescribe drugs that may slow the decline in memory and other cognitive skills. Also, we can educate caregivers and a person with Alzheimer's about strategies to enhance the living environment, establish routines, plan activities and manage changes in skills in order to minimize the effect of the disease on everyday life.

Importantly, an early diagnosis also helps a person with Alzheimer's disease, family and caregivers plan for the future. They have the chance to make informed decisions on a number of issues, such as:

  • Appropriate community services and resources
  • Options for residential and at-home care
  • Plans for handling financial issues
  • Expectations for future care and medical decisions

When we tell a person and family members about an Alzheimer's diagnosis, we help them understand that Alzheimer's is not an all-or-nothing phenomenon. We talk about what capacities are preserved and look to keep a person as healthy and safe as possible.

Last Updated: 2010-11-11
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